We don't expect Chipzilla to launch Arc GPUs until March but already a few leaks are coming out which gives us an idea what to expect. Reputed leaker on Twitter, HXL, posted an image on their handle which shows the 1st Gen Arc Alchemist SKU lineup for notebook GPUs.

While it has been known what the execution units (EU) count for Arc GPUs will be, the memory sub-system was a mystery with the top-end and lowermost SKUs at 16GB and 4GB. HXL's leak shows the memory configuration like memory interface width and maximum bandwidth.

There is no 6GB VRAM part for the mobile lineup as both SKU4 and SKU5 will feature only 4GB of memory. We did expect 18Gbps GDDR6 VRAM on the flagship SKU1 part instead of the 16Gbps so this is disappointing. Faster 18Gbps memory could still be a part of the desktop Alchemist (DG2) lineup just not headed for mobile markets.
The 448 EU Alchemist GPU that leaked towards the end of last year is missing, but that could also be a desktop only thing.